Mutation details: In the mutant allele a transition from G to A at nucleotide 1907 disrupted an Fnu4HI site in exon 3. This mutation changed the seventh amino acid in the A chain of mature insulin, Cys96 (TGC), to Tyr (TAC). The authors predict that the transition would disrupt a disulfide bond between the A and the B chains and would likely induce a major conformational change in insulin 2 molecules. RT-PCR studies suggest that both normal and mutant Ins2 alleles are transcribed similarly in pancreatic islets of heterozygous mice, although immunofluorescence and immunoblot analyses of heterozygous islets detected reduced levels of insulin and proinsulin.
(J:51935)